Orange oil is an

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

produced by cells within the rind of an

orange fruit An orange is a fruit of various citrus species in the family Rutaceae (see list of plants known as orange); it primarily refers to ''Citrus'' × ''sinensis'', which is also called sweet orange, to distinguish it from the related ''Citrus × ...

(''Citrus sinensis'' fruit). In contrast to most essential oils, it is extracted as a

by-product A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be consid ...

of orange juice production by

centrifugation Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate ...

, producing a cold-pressed oil. It is composed of mostly (greater than 90%)

d-limonene Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the essential oil, oil of citrus fruit peel (fruit), peels. The -isomer, occurring more commonly in nature as the fragrance o ...

, and is often used in place of pure d-limonene. D-limonene can be extracted from the oil by

distillation Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...

Composition

The compounds inside an orange oil vary with each different oil extraction. Composition varies as a result of regional and seasonal changes as well as the method used for extraction. Several hundred compounds have been identified with

gas chromatograph Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, ...

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is use ...

. Most of the substances in the oil belong to the

terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n > 1. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. Terpenes ar ...

group with

limonene Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels. The -isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring ag ...

being the dominant one. Long chain

aliphatic In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated, like hexane, or ...

hydrocarbon alcohols and

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

s like 1-octanol and

octanal Octanal is the organic compound, an aldehyde, with the chemical formula CH3(CH2)6CHO. A colorless fragrant liquid with a fruit-like odor, it occurs naturally in citrus oils. It is used commercially as a component in perfumes and in flavor produ ...

are second important group of substances. The presence of sinensetin, a flavone, explains the orange color.

Uses

Structural pest control

In the United States, d-Limonene (Orange Oil) is an EPA approved and registered active ingredient in California and Florida for the extermination of drywood termites, Formosan termites, and other structural pests. It is the active ingredient of the popular structural termiticide XT-2000. Regarded an alternative to traditional fumigation, d-Limonene orange oil is increasing in popularity as approximately 70% of modern consumers in California prefer local structural chemical injections over traditional "tenting" or fumigation.

Biological pest control

Orange oil can be used in

green pesticide Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad-based approach that integrates both chemical and non-chemical practices for economic control of pests. IPM aims to suppress pest populations below the econ ...

s for

biological pest control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...

. It can exterminate or control

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...

s and other insects by erasing their scent-

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

trail indicators, or dissolving their

exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...

, eliminating the infestation or disrupting re-infestation. Orange oil is also known to be useful to control, but not exterminate, drywood termites (''Incisitermes''), killing only those who come into direct contact with it.

Domestic cleaning agent

Orange oil is used as a cleaner. It is also used as an additive to certain wax finish/polish such as Howard's Feed-N-Wax Wood Polish & Conditioner.

Aromatherapy

Aromatherapy Aromatherapy is based on the usage of aromatic materials including essential oils and other aroma compounds, with claims for improving psychological and physical well-being. It is offered as a complementary therapy or as a form of alternative m ...

is a

pseudoscience Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or falsifiability, unfa ...

, with the purported evidence for

health effects Health effects (or health impacts) are changes in health resulting from exposure to a source. Health effects are an important consideration in many areas, such as hygiene, pollution studies, occupational safety and health, ( utrition and health sc ...

coming from preliminary research.

Hazards

The limonene which is the main component of the oil is a mild irritant, as it dissolves protective skin oils. Commercial use of orange oil, like that found in XT-2000 requires the use of protective gloves, according to EPA approved labeling and most municipal structural pest control law such as the California Structural Pest Control Act of 2015. Limonene and its oxidation products are skin irritants, and limonene-1,2-oxide (formed by aerial oxidation) is a known skin sensitizer. Most reported cases of irritation have involved long-term industrial exposure to the pure compound, e.g. during degreasing or the preparation of paints. However a study of patients presenting dermatitis showed that 3% were sensitized to limonene. Limonene has been observed to cause cancer in male rats by reacting with major urinary protein α2u-globulin, which is not produced by female rats. There is no evidence for carcinogenicity or genotoxicity in humans. The

IARC IARC may refer to: * International Aerial Robotics Competition * International Age Rating Coalition * International Agency for Research on Cancer * International Arctic Research Center * Israel Amateur Radio Club The Israel Amateur Radio Club (IA ...

classifies ''d''-limonene under Class 3: ''not classifiable as to its carcinogenicity to humans''. Limonene is also

flammable A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...

References

External links

The Effect of Citrus Oils on Fruit Flies
{{citrus Orange production Essential oils Vegetable oils Flavors Plant toxin insecticides Biological pest control